Identification of the Related Substances in Ampicillin Capsule by Rapid Resolution Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry

Table 3

Results of identification of the unknown related substances in ampicillin capsule.

Peak number	RT (min)	MS ()	MS^2 ()	Identification
9	11.1	566.1 [M + H]^+	407.1; 248.1; 191.0	Ampicilloic acid and 6-APA oligomer
12	13.9	548.1 [M + H]^+	443.1; 358.1; 199.0	6-APA ampicillin amide
13	15.2	673.2 [M + H]^+	655.1; 514.1; 324.1; 191.0	Ampilloic acids and ampicilloic acids oligomer
14	15.5	483.1 [M + H]^+	439.1; 350.1; 239.1; 160.0	Isomer of D-phenylglycyl ampicillin